<article class="" id="post-">
<header class="entry-header">
<h1 class="entry-title">.has()</h1>
<div class="entry-meta">
						所属分类：<span class="category"><a href="/category/traversing/">遍历</a> &gt; <a href="/category/traversing/filtering/">过滤</a></span>
<span class="pull-right">英文文档：<a href="https://api.jquery123.com/has/" target="_blank">.has()</a></span>
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</header><!-- .entry-header -->
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<div class="entry-content">
<article class="entry method" id="has1"><h2 class="section-title">
<span class="name">.has( selector )</span><span class="returns">返回: <a href="/Types/#jQuery">jQuery</a></span>
</h2>
<div class="entry-wrapper">
<p class="desc"><strong>描述: </strong>
			  筛选匹配元素集合中的那些有相匹配的选择器或DOM元素的后代元素。</p>
<ul class="signatures">
<li class="signature" id="has-selector">
<h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.4/">1.4</a></span>.has( selector )</h4>
<ul><li>
<div><strong>selector</strong></div>
<div>类型: <a href="/Types/#String">String</a>
</div>
<div>一个用于匹配元素的选择器字符串。</div>
</li></ul>
</li>
<li class="signature" id="has-contained">
<h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.4/">1.4</a></span>.has( contained )</h4>
<ul><li>
<div><strong>contained</strong></div>
<div>类型: <a href="/Types/#Element">Element</a>
</div>
<div>用于匹配元素的DOM元素。</div>
</li></ul>
</li>
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<div class="longdesc" id="entry-longdesc">
<p>如果提供一个jQuery对象代表DOM元素集合， <code>.has()</code> 方法会用其子集创建一个新的jQuery对象。提供的选择器会一一测试原先那些匹配元素的后代，含有匹配后代的元素会保留在结果中。</p>
<p>下面是一个嵌套列表的页面：</p>
<div class="syntaxhighlighter xml nogutter">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
<div class="line n4">4</div>
<div class="line n5">5</div>
<div class="line n6">6</div>
<div class="line n7">7</div>
<div class="line n8">8</div>
<div class="line n9">9</div>
<div class="line n10">10</div>
<div class="line n11">11</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code> <span class="tag">&lt;<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 1<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 2</code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>      <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 2-a<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>      <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 2-b<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;/<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 3<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">li</span>&gt;</span>list item 4<span class="tag">&lt;/<span class="title">li</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">ul</span>&gt;</span></code></div></div></pre>
</td>
</tr>
</tbody>
</table>
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<p>我们可以用如下方式对列表项集合应用这个方法：</p>
<div class="syntaxhighlighter javascript nogutter">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code>$(<span class="string">'li'</span>).has(<span class="string">'ul'</span>).css(<span class="string">'background-color'</span>, <span class="string">'red'</span>);</code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<p>
			      结果是 item 2 背景变成了红色，因为只有这个 <code>&lt;li&gt;</code> 含有 <code>&lt;ul&gt;</code> 后代。</p>
</div>
<section class="entry-examples" id="entry-examples"><header><h2 class="underline">例子:</h2></header><div class="entry-example" id="example-0">
<h4><span class="desc">检测是否一个元素在另一个之内。</span></h4>
<div class="syntaxhighlighter xml ">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
<div class="line n4">4</div>
<div class="line n5">5</div>
<div class="line n6">6</div>
<div class="line n7">7</div>
<div class="line n8">8</div>
<div class="line n9">9</div>
<div class="line n10">10</div>
<div class="line n11">11</div>
<div class="line n12">12</div>
<div class="line n13">13</div>
<div class="line n14">14</div>
<div class="line n15">15</div>
<div class="line n16">16</div>
<div class="line n17">17</div>
<div class="line n18">18</div>
<div class="line n19">19</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code><span class="doctype">&lt;!DOCTYPE html&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">html</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">style</span>&gt;</span><span class="css"></span></code></div></div><div class="container"><div class="line"><code>  <span class="class">.full</span> <span class="rules">{ <span class="rule"><span class="attribute">border</span>:<span class="value"> <span class="number">1</span>px solid red;</span></span> <span class="rule">}</span></span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">style</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">script</span> <span class="attribute">src</span>=<span class="value">"https://code.jquery.com/jquery-latest.js"</span>&gt;</span><span class="javascript"></span><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">ul</span>&gt;</span><span class="tag">&lt;<span class="title">li</span>&gt;</span>Does the UL contain an LI?<span class="tag">&lt;/<span class="title">li</span>&gt;</span><span class="tag">&lt;/<span class="title">ul</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">script</span>&gt;</span><span class="javascript"></span></code></div></div><div class="container"><div class="line"><code>  $(<span class="string">"ul"</span>).append(<span class="string">"&lt;li&gt;"</span> + ($(<span class="string">"ul"</span>).has(<span class="string">"li"</span>).length ? <span class="string">"Yes"</span> : <span class="string">"No"</span>) + <span class="string">"&lt;/li&gt;"</span>);</code></div></div><div class="container"><div class="line"><code>  $(<span class="string">"ul"</span>).has(<span class="string">"li"</span>).addClass(<span class="string">"full"</span>);</code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">html</span>&gt;</span></code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<h4>Demo:</h4>
<div class="demo code-demo"></div>
</div></section>
</div></article> </div>
</article>